The invention relates to improvements in apparatus for cleaning pipelines for beverages and the like. More particularly, the invention relates to improvements in apparatus of the type disclosed in commonly owned U.S. Pat. No. 4,607,410 and in commonly owned German Pat. No. 33 47 003.
Apparatus which are disclosed in the aforementioned patents employ a four-way shuttle valve wherein the valve body has an inlet for fresh liquid cleaning agent, an outlet for spent cleaning agent and two ports which are connectable with the ends of a pipeline to be cleaned. The valve body confines a reciprocable valving element in the form of a shuttle which is movable by the cleaning agent between a first position to connect the inlet for fresh cleaning agent with one of the ports while the other port communicates with the outlet so that the cleaning agent can flow from the inlet to the one port, through the pipeline and through the other port on to the outlet, and a second position in which the flow of cleaning agent is reversed, i.e., from the inlet to the other port, through the pipeline and through the one port on to the outlet. The means for reversing the direction of flow of cleaning agent, i.e., for initiating the movements of the shuttle between its two positions comprises one or more normally spherical cleaning elements, e.g., solid pearls or balls of sponge rubber or other material. The cleaning element or elements can obstruct the flow of fluid through passages (e.g., sets of holes) which are provided in the ends of the shuttle to thereby enable the cleaning agent to move the shuttle relative to the body of the shuttle valve.
The cleaning agent is tap water or another liquid, and such agent is supplied at a certain pressure in order to ensure that a stream of cleaning agent will flow from the inlet, through the pipeline and toward and into the outlet when the apparatus is in use. It is also known to employ a pump which supplies fresh liquid cleaning agent at a desired pressure. The diameter of the normally spherical cleaning element or elements can approximate the inner diameter of the pipeline to thus enhance the cleaning action when the cleaning element or elements are compelled to advance from one of the ports, through the pipeline and to the other port or in the opposite direction.
It has been found that the shuttle of the shuttle valve often fails to move from the one to the other position when the cleaning element or elements reach the one or the other port of the valve body. Attempts to reduce the likelihood of jamming of the shuttle in the one or the other position by reducing friction between the shuttle and the body of the valve have met with limited success. Failure of the shuttle to invariably move from the one to the other position in response to completed advancement of the cleaning element or elements from the one to the other end of the pipeline reduces the likelihood of predictable cleaning of the interior of the pipeline and entails losses in cleaning fluid because the apparatus must be operated for longer intervals of time if the number of reversals in the direction of flow of cleaning agent per unit of time is less than expected.